The Drake Equation attempts to estimate how many intelligent civilizations may have developed over time in a given area of space. One of the most important factors in the equation is the length (L) of time that a civilization exists. This is wide open to speculation and it is tempting to assume that an advanced intelligent civilization would last either forever or at least for a very long time. In these cases, the L factor becomes a time span from the incept of the civilization to now.

The L factor is specially crucial because not only are intelligent civilizations likely to be spread out in space, but also across time.

The standard size for an Olympic swimming pool is 50 meters long and 25 meters wide. Imagine a square pool half that size; 25 meters by 25 meters and around 9 feet deep. Throw into that pool a pea. The average pea is about 1/8 inch in diameter. The pool represents our galaxy, the Milky Way. The pea represents how far into the galaxy, our electromagnetic (radio and TV) ripples have spread over the last 100 years or so. 100 years from now, the pea will be twice that big or about 1/4 inch in diameter. After the ripples have been spreading for another 700 years from now, the pea will be about 1 inch in diameter. The pool will remain the same size. Our technology will have advanced.

The L factor makes it likely that any potential contact between civilizations would involve a large discrepancy in civilization age and therefore also in maturity of technology and ethics.Old Intelligence is Already Here

A civilization that is not just advanced technologically, but also advanced spiritually and ethically might have both the ability and the motivation to shelter our growth and development while remaining invisible to us. Perhaps our efforts to search for alien intelligence should be centered at home.

But the L factor should not be considered as age of the civilization and it is not necessary to consider the “end” of a civilization as the only limiting factor. As the technology of a civilization advances, it reaches a point where the contact can be limited to one-way communication. The advanced civilization will have the ability to study the more primitive civilization without them knowing about it.

When using the Drake Equation, consider the L factor to be a time period from the beginning of a civilization to the point where it can conceal it’s presence from other civilizations. Of course, this will be relative to development stage – two advanced civilizations might be able to detect each other when a primitive civilization would not. But the concept is still useful.

Our civilization seems to be very close to a massive transition in intelligence that we call, “the singularity” and this has taken place in a relatively small time frame, only tens of thousands of years at the most, since the beginning of what we consider to be the history of our civilization. If other intelligent civilizations also experience growth curves that anywhere near this (even allowing for large variations in rate), and experience a singularity-like transition event, the likelihood of two civilizations establishing communications during this time becomes very small. This leaves us with a universe populated by many intelligent civilizations, but always finding themselves alone, only able to communicate with amoebas below them on the developmental scale and something undefinable above them.